Air flow rates

[Quetech]

I am looking at several extractors of the chip type and
was wondering what sort of airflow rates are required.
I see fox do one with a flow rate of 2500 m/min.
Do I need one this high or will 1000 be enough

Mike

 

[davy_owen_88]

What are you planning on extracting from? As a general rule, get the most powerful you can afford, too much airflow is not going to harm the machine and will just collect more of the dust - which is a good thing.

If you are only collecting chippings i.e you are only going to connect the extractor to a planer/thicknesser then you don't really need as much airflow since its the fine dust that requires the higher airflow. If you intend on plumbing it all in then get the highest you can as static pressure loss will factor in and you won't get the same airflow at the end of the ducting as you do at the start.

If you plan on collecting fine dust then you will have to upgrade the filter. No high volume dust extractor within a reasonable price range will come with filters suitable for fine dust (anything below 1 micron). High volume extractors require large filter surface areas and to cut costs most high volume extractors are just shipped as 'chip collectors' so a standard 5 micron or more filter will do.

There are also many threads about dust extraction on this forum... most turn into an argument about what the required airflow is and whether so and so's extractor is actually as good as someone elses. But if you stick to getting the best you can afford then you won't go far wrong.

Hope this helps.
Davy

 

[user 2070]

I have a chip collector type which is rated at 1000m3 per hour and collects the dust and chips happily from a 305mm saw or a 260mm planer/thicknesser. It is fitted with a fine filter which some claim increases the flowrate because of its additional surface area from pleating. (5m2 compared with 1m2)

However, it is fitted with 100mm ducting and when I tried to connect it to a router dust spout via a 25mm hose it was almost useless! For the orbital sander, hand-held routers, belt-sander and Rotex150, I use another device which has a lower volume flowrate but is capable of producing a much higher pressure difference (more like a vacuum cleaner).

I do not believe that the vacuum cleaner type unit would have a high enough flowrate to persuade the sawdust and fine dust from the saw to run down the extraction ports, and with only 22litre bags it would be expensive to connect to the planer/thicknesser - and probably would not collect the chips effectively anyway.

So, for my applications I concluded that I needed two different devices ($$$).

I would not use any dust collector without a fine filter, but that is my own personal choice (and money!) ;-)

Simon

 

[Quetech]

Thanks for the info guys.
I will be using the extractor to suck from my table saw as well as a planer so there will be fine dust involved
However I plan to have the extractor outside the workshop were this type of bag filter machine belongs.
I don't have any concerns regarding workshop heating as the machine won't be running that long and I would also rather affect the workshop heat than my health.
I already have a fein vacuum type extractor for my router/sanders so the
big extractor will only be used for the large machines.

Mike

 

[Pecker]

since you already have a fine filter solution for the sander, any chip collector will do the rest. however, since you are having it out side, you need to watch the length of run for the hose/pipework as has already been mentioned, so basically the bigger the flow rate the better.
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